Self assessment deadlines for 2025/26: The dates you need to know
Updated: 2 hours ago
When it comes to self assessment, there are a few important dates worth putting in your calendar.
Whether you're filing for the first time or you've been completing tax returns for years, here's what you need to know about the 2025/26 tax year.
What period does the 2025/26 tax return cover?
The 2025/26 tax year runs from 6 April 2025 to 5 April 2026.
Your tax return reports the relevant income, expenses and other tax information for that period.
5 October 2026: Registration deadline
If you needed to complete a tax return for 2025/26 and weren't already registered, the usual deadline to notify HMRC was 5 October 2026.
If you've missed it, don't ignore it. Register as soon as possible to reduce the risk of further problems.
31 October 2026: Paper tax return deadline
If you're submitting a paper tax return, HMRC must receive it by 31 October 2026.
This deadline doesn't apply if you're filing online.
31 January 2027: Online filing and payment deadline
This is the big one!
Your online 2025/26 self assessment tax return must usually be submitted by 31 January 2027.
Any outstanding tax for the year is generally due by the same date.
If payments on account apply, your first payment towards the 2026/27 tax year may also be due.
31 July 2027: Second payment on account
If you're required to make payments on account, your second instalment towards the 2026/27 tax year will normally be due on 31 July 2027.
Not everyone needs to make these advance payments, so it's worth checking your own calculation.
Why file early?
You don't need to wait until January!
Getting your tax return completed early means you'll know what you owe, have more time to budget and avoid the last-minute rush.
And the best bit? Filing early doesn't usually mean paying your tax early.
Ready to get your tax return sorted?
Returnly makes straightforward self assessment tax returns simple, with a fixed fee of £199 including VAT.
Check your eligibility and get started online.